Field of the Invention
This invention relates generally to tape cassettes and, more specifically, is directed to a tape cassette of the type in which the cassette casing has a recess in a front portion thereof with openings therefrom facing forwardly and downwardly, respectively, a lid is pivotally mounted on the casing for movement between a closed position extending across the forwardly facing opening and a raised opened position uncovering the forwardly facing opening, a tape is wound about reels rotatable in the casing and extends between the reels in a path including a run extending across the forwardly facing opening so as to be disposed in back of the lid in its closed position, and a shutter is slidable relative to a bottom surface of the cassette casing between a closed position in which the shutter closes the opening facing downwardly from the recess and a rearwardly displaced opened position in which the downwardly facing opening is uncovered for providing access to the tape run.
Description of the Prior Art
Tape cassettes are known for digitally recording and reproducing data or information. Such cassettes generally include a casing having a recess at the front of the cassette casing with openings facing forwardly and downwardly, respectively, from such recess, a tape wound about a pair of reels rotatable within the casing and extending between such reels in a path having a run extending across the forwardly facing opening so as to be disposed in back of the lid in its closed position, and a shutter slidable relative to the bottom surface of the casing between a closed position in which the shutter closes the downwardly facing opening and a rearwardly displaced opened position uncovering the downwardly facing opening so that, with the lid also in its opened position, access may be had to the tape run so as to make possible recording or reproducing operations thereon.
More specifically, as shown in FIGS. 21 and 22, a so-called digital audio tape (DAT) cassette 100 includes a substantially rectangular, box-shaped casing 101 which may be formed of upper and lower shell portions joined by adhesive, ultrasonic welding or the like. A pair of reels 102 shown in dotted lines on FIG. 22 are rotatable within the casing 101, and a magnetic tape (not shown) is wound about the reels 102 and extends therebetween in a path having a run that extends across an opening facing forwardly from a recess 101b formed in the front portion of the casing 100. A lid 103 is pivoted on the casing 101 for movements between a closed position shown on FIGS. 21 and 22 in which the lid 103 covers the tape run extending across the forwardly facing opening from the recess 101b and an opened position swung upwardly from the position shown on FIG. 21, and in which the tape run extending across the forwardly facing opening of the recess 101b is uncovered or exposed. With the lid 103 in its opened position, access may be had to the tape run through a downwardly facing opening from the recess 101b for effecting digital recording and reproducing operations on the exposed tape.
In order to close the downwardly facing opening of the recess 101b and thereby protect the tape when the cassette 100 is not in use, the illustrated cassette according to the prior art is further shown to include a channel-shaped shutter 104 which is slidable relative to the bottom surface 101a of the casing 101 between a closed position shown on FIGS. 21 and 22 and an opened position (not shown) in which the shutter 104 is displaced rearwardly away from the front of the casing 101 so as to uncover the downwardly facing opening of the recess 101b. The shutter 104 is shown on FIG. 22 to have a pair of laterally spaced apart reel access openings 104a which, in the opened position of the shutter 104, register with corresponding reel access openings 102a formed in the bottom 101a of the casing 101, as shown in broken lines on FIG. 22. The undersurface of the shutter 104 is shown to have two laterally spaced apart grooves 104b formed parallel to the direction of movement of the shutter in the forward portion of the latter so as to be disposed laterally outward in respect to the recess 101b in the casing. As shown on FIGS. 22 and 23, each of the grooves 104b has a keeper opening 104c formed therein adjacent the back end of the respective groove, while a similar keeper opening 104d is formed in each groove 104b adjacent the forward end thereof. The front portion of the lid 103 has laterally spaced apart cut outs 103a formed in its lower edge so as to be aligned with the forward ends of the grooves 104b, respectively, when the lid 103 and shutter 104 are in their respective closed positions. At laterally spaced apart positions corresponding to the locations of the grooves 104b, the bottom 101a of the casing 101 has slots 101c for defining the sides and free ends of resilient latch fingers 101c. Each latch finger 101c has, at its free end, a depending locking nose or projection 101d which, in the closed position of the shutter 104 shown on FIG. 23, extends through the keeper opening 104c into the respective groove 104b for holding the shutter in its closed position. On the other hand, when the shutter is moved to its opened position, each nose or projection 101d extends through the keeper opening 104d into the respective groove 104b for holding the shutter 104 in its opened position against the force of a spring or other resilient means (not shown) providing for biasing the shutter 104 toward its closed position. Each locking nose or projection 101d is shown to have a beveled lower end so that a releasing element (not shown), when moved through the cutout 103a and along the respective groove 104b, can act on the beveled lower end of the nose or projection 101d for deflecting the latter upwardly out of the keeper opening 104c or 104d so as to permit movement of the shutter 104 between its closed and opened positions.
Although the resilient fingers 101c formed as integral parts of the bottom 101a of the casing 101 yeildably urge the respective locking noses or projections 101d to remain engaged in the keeper openings 104c or 104d until displaced upwardly therefrom by respective releasing elements, as described above, the known digital tape cassette described with reference to FIGS. 21-23 has a disadvantage in that vibrations generated during loading of the cassette into a recording and/or reproducing apparatus, such as, a DAT deck, a digital VCR, or the like, may cause the locking noses or projections 101d to become disengaged from the respective keeper openings 104c or 104d. Further, the shutter 104 must be thick enough to allow for the formation therein of the elongated grooves 104b, which thereby limits the extent to which the thickness of the shutter 104 may be reduced. Further, the need to provide the shutter 104 with a substantial thickness limits the designers freedom of choice in producing the described cassettes. For example, if it is desired to form the shutter 104 of metal, such metal would have to be undesirably thick so as to accommodate the grooves 104b therein. Further, if the shutter 104 is formed of metal while the casing 101 is molded of a synthetic resin, the hard metal of the shutter may scratch or scrape material from the casing during repeated movements of the shutter between its opened and closed positions. On the other hand, limiting the choice of material for the shutter 104 to a synthetic resin also restricts the designers freedom in producing the tape cassette.
The known digital tape cassette described above with reference to FIGS. 21-23 is further disadvantageous in that, when the shutter 104 is closed, the condition of the tape extending across the opening facing forwardly from the recess 101b cannot be readily determined by a user. In other words, with the lid 103 and the shutter 104 in their closed positions, the user cannot determine whether the tape extending between the reels 102 is slack.